Arachnophobia is among the most common phobias and can have upsetting consequences, from panic attacks to arachnophobes avoiding everyday occasions due to fear of encountering a spider.

A well-established treatment for arachnophobia and similar phobias is exposure therapy, in which patients are guided by a therapist through more and more stimulating or realistic exposures to their fear. For instance, the patient may begin by looking at a cartoon spider and progress to handling a tarantula.

Arachnophobes can be reluctant to partake in exposure therapy, however, due to fear of exposing themselves to real spiders towards the end of treatment. Hoping to reassure arachnophobes, the Basel team developed an AR app, Phobys, based on established principles of exposure therapy: “It’s easier for people with a fear of spiders to face a virtual spider than a real one,” explained Anja Zimmer, who led the study.

The app projects a realistic 3D spider model onto the...